U.S. Ambassador to France Jane Hartley (C), three U.S. citizens student Anthony Sadler (L), Airman First Class Spencer Stone (2ndL) and National Guardsman Alek Skarlatos (2ndR) arrive to attend a ceremony at the Elysee Palace in Paris, France, August 24, 2015. French President Francois Hollande on Monday will award France's highest honour, the Legion d'honneur, to three U.S. citizens and a Briton who helped disarm a machine gun-toting attacker on a Thalys train last week. REUTERS/Philippe Wojazer